Re: ip_conntrack related slab error (Re: Fw: Re: 2.6.16-rc1-mm3)

From: Reuben Farrelly
Date: Tue Jan 31 2006 - 05:06:22 EST




On 31/01/2006 10:24 p.m., Harald Welte wrote:
Begin forwarded message:

Date: Sat, 28 Jan 2006 00:47:06 +1300
From: Reuben Farrelly <reuben-lkml@xxxxxxxx>
To: Andrew Morton <akpm@xxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx, netdev@xxxxxxxxxxxxxxx
Subject: Re: 2.6.16-rc1-mm3

Just triggered this one, which had a fairly bad effect on connectivity to the box:

i2c /dev entries driver
slab error in kmem_cache_destroy(): cache `ip_conntrack': Can't free all objects
[<b010412b>] show_trace+0xd/0xf
[<b01041cc>] dump_stack+0x17/0x19
[<b0155d04>] kmem_cache_destroy+0x9b/0x1a9
[<f0ebf701>] ip_conntrack_cleanup+0x5d/0x10e [ip_conntrack]
[<f0ebe31e>] init_or_cleanup+0x1f8/0x283 [ip_conntrack]
[<f0ec2c4e>] fini+0xa/0x66 [ip_conntrack]
[<b0136d06>] sys_delete_module+0x161/0x1fb
[<b0102b3f>] sysenter_past_esp+0x54/0x75
Removing netfilter NETLINK layer.
[root@tornado log]#

I was just reading IMAP mail at the time, ie same as I'd been doing for an hour or two beforehand and not altering config of the box in any way. I was able to log on via console but lost all network connectivity and had to reboot :(

The codepath you see in that backtrace is only hit during load or
removal of the 'ip_conntrack' module. While this certainly still should
not oops, your description of 'not doing anything but IMAP reading' is
certainly not true.

Could you please describe what actually happened when that bug happened?
It looks to me that you were unloading ip_conntrack_netlink.ko followed
by ip_conntrack.ko.

This just happened, in fact while I was typing up my previous mail. I only noticed because I went to send and connection to the server timed out:

I'm not sure if this is related or not.


Fedora Core release 4 (Rawhide)
Kernel 2.6.16-rc1-mm4 on an i686

tornado.reub.net login: BUG: unable to handle kernel paging request at virtual address 00200200
printing eip:
f0eb410d
*pde = 00000000
Oops: 0000 [#1]
SMP
last sysfs file: /block/fd0/dev
Modules linked in: nfsd exportfs lockd sunrpc lm85 hwmon_vid eeprom ipv6 ip_gre iptable_filter iptable_nat ip_nat ip_conntrack nfnetlink iptable_mangle ip_tables binfmt_misc ide_cd cdrom serio_raw hw_random piix i2c_i801
CPU: 0
EIP: 0060:[<f0eb410d>] Not tainted VLI
EFLAGS: 00010292 (2.6.16-rc1-mm4 #2)
EIP is at ip_nat_cleanup_conntrack+0x22/0x62 [ip_nat]
eax: dbcb0570 ebx: d6f9164c ecx: d6f916c8 edx: 00200200
esi: d6f9164c edi: eef02380 ebp: b044ce74 esp: b044ce70
ds: 007b es: 007b ss: 0068
Process smbd (pid: 2517, threadinfo=b044c000 task=dbcb0570)
Stack: <0>d6f9164c b044ce88 f0ec0251 00004599 d6f9164c d52aca80 b044cee4 b02e9914
b044ceb4 b02c6b49 00000000 00000277 00000277 00000002 0100007f 0100007f
b0487508 b044cee4 b02c6d6d 02772e80 027747ab ef856ff4 b02cd972 80000000
Call Trace:
[<b0103bf5>] show_stack_log_lvl+0xc5/0xea
[<b0103db7>] show_registers+0x19d/0x22b
[<b0103f61>] die+0x11c/0x22c
[<b01140e4>] do_page_fault+0x27a/0x5de
[<b0103737>] error_code+0x4f/0x54
[<f0ec0251>] destroy_conntrack+0x4c/0x13e [ip_conntrack]
[<b02e9914>] tcp_v4_rcv+0xad9/0xb25
[<b02ce33e>] ip_local_deliver+0x92/0x2d4
[<b02cdfd2>] ip_rcv+0x331/0x60b
[<b02b3638>] netif_receive_skb+0x219/0x302
[<b02b506b>] process_backlog+0x8e/0x12e
[<b02b51c6>] net_rx_action+0xbb/0x1c4
[<b01213cd>] __do_softirq+0x70/0xd7
[<b0105071>] do_softirq+0x4f/0x53
=======================
[<b0121480>] local_bh_enable+0x4c/0x79
[<b02b536d>] dev_queue_xmit+0x9e/0x305
[<b02d3d72>] ip_output+0x17d/0x32b
[<b02d31d2>] ip_queue_xmit+0x240/0x53e
[<b02e2562>] tcp_transmit_skb+0x3bd/0x6c9
[<b02e29b1>] tcp_send_ack+0xa2/0xdf
[<b02d826c>] cleanup_rbuf+0x40/0xf0
[<b02d9f59>] tcp_recvmsg+0x1b0/0x7b2
[<b02ab6ab>] sock_common_recvmsg+0x3d/0x53
[<b02a9b1e>] sock_recvmsg+0xda/0xfe
[<b02aae39>] sys_recvfrom+0x79/0xbe
[<b02aaeb4>] sys_recv+0x36/0x38
[<b02ab209>] sys_socketcall+0x158/0x254
[<b0102b3f>] sysenter_past_esp+0x54/0x75
Code: 5d c3 b9 60 73 eb f0 eb f5 55 89 e5 53 89 c3 f7 40 08 80 01 00 00 75 03 5b 5d c3 b8 40 73 eb f0 e8 f4 cc 45 bf 8d 4b 7c 8b 51 04 <3b> 0a 75 28 8b 43 7c 3b 48 04 75 2a 89 50 04 89 02 c7 43 7c 00
<0>Kernel panic - not syncing: Fatal exception in interrupt
<0>Rebooting in 60 seconds..

reuben
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